Flueric screamer



United States Patent M 3,415,193 FLUERIC SCREAMER Carl J. Campagnuolo, 'Chevy Chase, Md., and Raymond W. Warren, McLean, Va., assignors to the United States of America as represented by the Secretary of the Army Filed June 7, 1967, Ser. No. 645,096

-' 7 Claims. (Cl. 102-92.4)

ABSTRACT OF THE DISCLOSURE A flueric screamer is designed to be mounted on the nose of an ordnance projectile. The flueric screamer has a resonating cavity and is designed to have the ram air of the projectile alternately directed into and away from the resonating cavity. The continual entering and leaving of'ram air from the resonating cavity will generate high energy acoustic waves which will have a distressing effect upon enemy troops over which the projectile will pass on its way to a designated target.

Background of the invention This invention reates to the ordnance arts and in particular to a device for generating high energy acoustic waves as an ordnance projectile travels through the air on its way towards a designated target.

Ordnance projectiles are designed to explode at a designated target and to inflict harm upon the enemy due to the explosive material carried by the projectile. One method of also incapacitating the enemy is by inducing psychological fear in him. This could be accomplished by having a projectile generate high level acoustic waves, such as a whining sound, while passing over the enemy which would instill fear in the enemy and force him to keep his head down rendering him a less efiective fighting force. Prior art projectiles are quite efiicient in damaging an enemy by the explosive content therein but none were designed to emit a sufiiciently high energy acoustic wave to instill great psychological fear in the enemy as the projectile passed over him. Some prior art devices were capable of generating low energy acoustic waves but because of their intricate design and resulting poor aerodynamics they greatly aifected the range the projectile could travel and thus could not efliciently be used in a combatfsituation.

It is an object of the present invention to provide a device that can be attached to the nose of a projectile to generatehigh energy acoustic waves.

Another object of the present invention is to provide a device'that can be attached to the nose of a projectile to generate high energy acoustic waves and that will not alter the aerodynamics of the projectile.

Summary of the invention Briefly, in accordance with the present invention, a flueric screamer device is designed to be attached to the nose of a projectile. The flueric screamer includes a resonating cavity into which the ram air of the projectile is alternately directed into and away from. The entering and leaving of ram air from the resonating cavity generates high level acoustic waves which have a distressing etfect upon those in the immediate vicinity thereof.

Brie desdription of the drawings FIGURE 1 is a schematic representation of a flueric screamer attached to a projectile in accordance with the principles of the present invention, and

FIGURE 2 is a schematic representation of the flueric screamer shown in FIGURE 1.

Description of the preferred embodiment In FIGURE 1, a projectile 20 is shown having a flueric screamer 10 attached to its nose portion.

In FIGURE 2, the flueric screamer 10 is shown including a solid round body portion 17 which has at the right end thereof a threaded portion 15 which is adapted to be screwed into the nose' of projectile 20. Body 17, adjacent threaded portion 15, is of constant cross-sectional area and at point 25 has a conical shape 14 which is truncated at the left-most portion thereof. A screamer ACP 13 is placed over left part of conical portion 14. Surrounding the constant cross-sectional part of body 17 is a hollow cylindrical member 16 open at its left end and closed at its right end. Cylindrical member 16 is of a larger cross-sectional area than the constant cross-sectional area part of body 17 and defines an annular resonating chamber 18 between the cylindrical member wall and the circumference body 17. Cylindrical member 16 can be attached to body 17 at the point adjacent nose plug 15 by any of the conventional means. The left end of cylindrical member 16 has a sharp edge 40 for a purpose soon to be described.

Operation When the projectile to which screamer 10 is attached is sent through the air, ram air will pass over the screamer cap and is directed into resonating cavity 18. This will tend to build up the pressure in resonating cavity 18 to force ram air away from the resonating cavity to ambient. As the ram air travels adjacent the resonating cavity towards ambient, it will tend to entrain the fluid in resonating cavity 18 creating a low pressure region there. This will again draw the ram air into resonating cavity 18 and the cycle will be continually repeated with high energy acoustic waves being generated as a result thereof.

The sharp edge 40 of cylindrical member 16 help to direct ram air away from chamber 18.

The frequency (f) of oscillation of the fiueric screamer in accordance with the present invention can be repre sented by:

L a m 41rL (p wherein By adjusting the length of the cavity and with a knowledge of the temperature and pressure of the air through which the projectile shall be directed, it is possible to obtain frequencies and sound levels which will create maximum psychological fear among enemy troops over which the projectile shall pass. The flueric screamer can be used with explosive projectiles that fly subsonic or supersonic. If the flueric screamer is attached to a highly supersonic shell, having a Mach number approximately 2 or 3, the sound emitted from the shell travelling through the air will be heard only after the boom from the initial shock wave has passed over the listener.

It is obvious that the term projectile is generic and our invention can be used with any thrust propelled ordnance device.

If it is desired to make the screamer sensitive to a wide range of projectile velocities resonating chamber 18 can be made conically shaped rather than cylindrical as shown.

While we have described and illustrated a specific embodiment of our invention, it will be clear that variations of the details of construction which are specifically illustrated and described may be resorted to Without departing from the true spirit and scope of the invention as defined in the appended claims.

We claim:

1. A device for generating high energy acoustic waves when attached to a projectile, comprising:

(a) first means defining a resonating cavity, and

(b) second means for directing ram air toward the entrance of said resonating cavity in such a manner that said resonating cavity will operate to alternately direct the ram air of said projectile into said resonating cavity and away from said resonating cavity.

2. A device for generating high energy acoustic waves when attached to a projectile comprising:

(a) a body of constant cross-sectional area having a portion to be connected to a nose of said projectile,

(b) a cylindrical member surrounding said body about said portion having said constant cross-sectional area and defining a resonating cavity, and

(c) means for directing ram air toward the entrance of said resonating cavity in such a manner that said resonating cavity will operate to alternately direct the ram air of said projectile into said resonating cavity and away from said resonating cavity.

3. A device according to claim 2 wherein said means includes a tapered portion integral with said constant cross-sectional area.

4. A device according to claim 3 wherein said tapered portion is truncated to form an end perpendicular to the axis of said body.

5. A device according to claim 4 wherein a screamer cap iszplaced over part of said truncated portion of said body and said end.

6. A device according to claim 5 wherein said cylindrical member is hollow and has an open end and a closed end, said open end to alternately receive and discharge said ram air of said projectile.

7. A device according to claim 6 wherein said cylindrical member has a sharp edge about its open end.

References Cited UNITED STATES PATENTS 644,361 2/1900 Luciani 10292.4 1,107,948 8/1914 Hoagland 102-91 2,247,111 6/1941 B-atchelor et a1. 10266 2,352,260 6/1944 Herman 10292.6 3,282,216 11/1966 Calfee et a1 102105 ROBERT F. STAHL, Primary Examiner. 

